Multiple layer hull

ABSTRACT

An improved multiple layer hull system may be used in vehicle applications. An upper hull may be monolithic or may have a plurality of seams. A sacrificial lower hull may be entirely U-shaped or partially flat-bottomed, or may have a U-shaped or partially flat-bottomed base with outwardly extending wings complementing a lower surface of the upper hull. A blast deflector may be beneath the lower hull or base either as a separate part or as an integral part.

STATEMENT OF GOVERNMENT INTEREST

This disclosure was made in part with Government support. The Government may have certain rights in the disclosure.

TECHNICAL FIELD

This disclosure relates to layered structures for vehicles, including vehicles that may be exposed to blasts. A layered structure may useful in, for example, military applications. Such a structure may provide blast mitigation and increase occupant survivability. The components of the layers in the structure may work synergistically with one another to mitigate the effects of a blast. The layered structure may have unexpected and advantageous results, including increased survivability for occupants without increasing the overall distance of a lowermost surface of a vehicle from a top surface of the ground.

BACKGROUND

Conventionally, a common approach to blast mitigation is to raise a military vehicle further away from the ground. Other conventional approaches included the adoption of V-hull structures, so named due to their general shape. Hulls are the main frame or the main body of a vehicle such as a ship or a tank. The “V” shape of such structures may increase the probability of deflection of material in a blast. Some known hulls for military include V-within-V hull structures.

Improvements to hull shapes and structures for mitigating blasts are in need, as are improvements that may increase survivability. It is somewhat counterintuitive that a multiple layer hull could provide one or more of these advantages without raising the occupant-carrying hull away from the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary layered hull structure;

FIG. 2 is an exemplary layered hull structure;

FIG. 3 is an exemplary layered hull structure;

FIG. 4 is an exemplary layered hull structure; and

FIGS. 5-1 to 5-2 are exemplary deformation patterns following blast.

DETAILED DESCRIPTION

All figures and examples herein are intended to be non-limiting; they are mere exemplary iterations and/or embodiments of the claims appended to the end of this description. Modifications to structure, materials, the order of steps in procedures, etc., are contemplated.

Referring to FIG. 1, exemplary hull 10 is shown. Hull 10 has multiple layers, including upper hull portion 12, sacrificial lower hull portion 14 and, optionally, blast deflector 16. In a blast event, each layer causes dissipation of energy, working to protect occupants. Additional layers, such as isolated, suspended floors, can assist with further energy dissipation and occupant protection. Unexpectedly, the multi-layered hull 10 is effective for blast mitigation and occupant protection at levels not previously achieved without raising the hull 10 further from the ground where a blast may originate.

In the non-limiting example of FIG. 1, upper hull portion 12 is monolithic. Where upper hull portion 12 is monolithic, the material comprising walls of the hull 10 may be thicker than in non-monolithic embodiments. The hull 10 may comprise any of a number of materials, including but not limited to steel, titanium, aluminum, composite armor, fiber-reinforced metals. An interior surface of the hull 10 may include any of a number of materials, including but not limited to spall liners, blast mats, energy absorbing materials, and more.

Lower hull portion 14 is shown as U-shaped, but it can take on a shape where at least a portion of the bottom of the “U” is flat or substantially flat rather than rounded or arcuate. Lower hull portion 14 may be of a monolithic structure, which may assist in resisting the effects of a blast. Lower hull portion 14 may be sacrificial, as in the exemplified embodiment, to reduce energy transmitted to the upper hull portion 12. Lower hull portion 14 may comprise a high-strength low mass material so it does not unduly contribute to the overall mass of the hull 10. Lower hull portion 14 may also provide fragmentation protection.

Lower hull portion 14 may be connected to the upper hull portion 12 through any of a number of mechanisms, including sacrificial connection mechanisms such as bolts expected to shear in a blast event in a controlled or planned manner to further absorb blast energy. Where such sacrificial connection mechanisms are used, the connection is described herein as “semi-decoupled.”

In some embodiments, the connection between the upper and lower hull may be formed at least in part from friction stir welding. In some embodiments, mechanical connections are made through plates, bolts such as shear bolts, insert plates and/or other connecting structures. In one embodiment, insert plates are attached to the lower hull. Different bolt thicknesses and a different number of bolts in the connection can lead to different separation characteristics in a blast event, as well as different patterns of energy absorption and dissipation through bolt shearing. In some exemplary embodiments, 60 total stainless steel bolts are used; in others 120. Bolts may range in diameter and material. Bolts shearing in a controlled manner may dissipate blast energy and protect soldiers in the hull 10.

Optionally, blast energy absorbing material may be placed or secured between the lower hull portion 14 and the upper hull portion 12. In such embodiments, the energy absorbing material may be attached to one or the other or both portions of hull 10. Lower hull portion 14 may be made from any of a number of materials, including but not limited to steel, composite armor, and other materials.

Blast deflector 16 may be separate from or integral with lower hull portion 14. If separate from lower hull portion 14, it may be attached to same using any of a number of attachment mechanisms, including semi-decoupled connections. Bolts, insert plates, and the like may be used to keep various sacrificial modules or portions in mechanical communication with one another. In the depicted embodiment, blast deflector 16 is V-shaped. Other shapes are contemplated, including U-shaped embodiments or shapes having a ground-facing component that is substantially V or U shaped. The walls of the V or the U may be concave or convex in shape rather than being substantially straight. Materials for the blast deflector 16 may be high strength/high stiffness and low mass so as not to contribute substantially to the overall mass of hull 10. Blast deflector 16 may improve blast deflection, distribute blast load, and/or reinforce structure.

Referring to FIGS. 2 and 3, hulls 20 and 30 are shown. Hulls 20 and 30 are not monolithic, but rather have at least one joint or seam. In the depicted non-limiting examples, the joints or seams run substantially along the longitudinal length of hulls 20 and 30. Other configurations are contemplated. The hulls 20 and 30 may be thinner and lighter than hull 10, especially where a portion of a bottom surface of hull 20 and 30 is supported by at least one “wing,” as explained below.

In hull 20, exemplary butt weld 27 a is shown on a top surface of upper hull portion 22 in a central region of same, and exemplary butt weld 27 b is shown on a bottom surface of upper hull portion 22 in a central region. Both butt welds create seams at the indicated locations running longitudinally relative to a length of a vehicle. In hull 30, exemplary butt weld 37 a and 37 c are in opposite end regions of a top surface of upper hull portion 32. Hull 30 also has butt weld 37 b in a bottom surface of upper hull portion 32. Although butt welds are exemplified, other type of joints are contemplated.

In lower hull portion 24 and lower hull portion 34, a partially flat bottom shape is adopted in the base of the lower hull. Optionally, a blast deflector 26 and 36 may be attached or semi-decoupled to the lower hull portion 24 and 34.

Other configurations are contemplated, including pointed or rounded bottom bases of the lower hull. In FIG. 2, the lower hull portion 24 also comprises wings 24 a and 24 b. Similarly, in FIG. 3, lower hull portion 34 comprises wings 34 a and 34 b. Wings, which are optional, may extend outwardly from the base of the lower hull, and run along a portion of bottom surface of a lower hull portion 24 and 34. The wings 24 a, 24 b, 34 a, and 34 b project outwardly at a different angle from the walls of the lower hull portions 24 and 34. As depicted, the length of the wings may run the same length of an angled portion of the bottom surface. The wings may be shorter or longer than the length of the angled portion of the bottom surface of lower hull portion 24 and 34. In embodiments such as hulls 20 and 30 where the lower hull portion 24 and 34 has wings, the upper hull portion 22 and 32 need not be as thick.

Referring to FIG. 4, hull 40 comprises multiple layers, including at least upper hull portion 42 and lower hull portion 44. In this exemplary embodiment, no wings are included in the lower hull portion 44. That is, the side walls of lower portion 44 extend from a flat bottom portion at a constant or substantially constant angle. Side walls need not be linear; they can take on or include arcuate (concave or convex) shapes or other shapes. The hull 40 may also include a sacrificial blast deflector 46. In the depicted example, hull 40 comprises three butt welds, 47 a, 47 b and 47 c. Other mechanisms of and placements for joining together structure to form a hull 40 are contemplated. The number and placement of such joints or seams may vary. For example is contemplated one more could be in a bottom central region, bottom end region, top central region, or a top end region. Side walls at various heights may also have such joints or seams.

Referring to all of exemplary multi-layered hulls of FIGS. 1-4, the upper hull portion may be of the same or different materials from the lower hull portion. Also, these exemplary embodiments describe a modular design that is resettable and field configurable. That is, portions can be upgraded and/or replaced as needed if a blast deflector, for example, is sacrificed.

Referring to FIGS. 5-1 and 5-2, exemplary hulls are shown in terms of predicted (simulated) responses to a blast event over time. FIG. 5-1 shows, from left to right, simulated deformation over time. FIG. 5-2 shows, from left to right, deformation over time. In particular, the deformation patterns are an improvement over prior hull structures at the same or a similar vertical distance from the ground.

Although the steps of the above-described processes have been exemplified as occurring in a certain sequence, such processes could be practiced with the steps performed in a different order. It should also be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps could be omitted. In other words, the descriptions of the processes are provided for the purpose of illustration, and should not limit the claimed invention.

Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the disclosure. For example, a different type of connecting mechanism may be used to attach the lower hull to an upper hull while still being in the scope of this invention. The scope of the invention should be determined with reference to the appended claims along with the full scope of equivalents. It is intended that future developments will occur, and that embodiments of the disclosed systems and methods will incorporate and be incorporated with such future developments.

Use of singular articles such as “a,” “the,” “said” together with an element means one or more of the element unless a claim expressly recites to the contrary. 

1. A multiple layer vehicle hull, comprising: an upper hull portion; a lower U-shaped or partially flat bottom shaped hull portion semi-decoupled to the upper hull portion by blast energy absorbing sacrificial connection mechanisms; and a blast deflector below and detachably connected to the lower hull portion.
 2. The vehicle hull of claim 1, wherein the upper hull portion is monolithic.
 3. The vehicle hull of claim 1, wherein the lower hull portion is monolithic.
 4. The vehicle hull of claim 1, wherein the lower hull portion is sacrificial.
 5. The vehicle hull of claim 1, wherein the blast deflector is V-shaped.
 6. The vehicle hull of claim 1, wherein the blast deflector is attachable to the lower hull portion.
 7. The vehicle hull of claim 1, wherein the blast deflector is integral with the lower hull portion.
 8. A multiple layer vehicle hull, comprising: an upper hull portion; a lower hull portion below the upper hull portion, the lower hull portion comprising a base with outward facing side wings atop the base; a blast deflector in mechanical communication with the base.
 9. The vehicle hull of claim 8, wherein the upper hull is monolithic.
 10. The vehicle hull of claim 8, wherein the lower hull portion is monolithic.
 11. The vehicle hull of claim 8, wherein the lower hull portion wings each have a length and an angle to support an angled portion of a bottom surface of the upper hull.
 12. The vehicle hull of claim 8, wherein the lower hull portion is sacrificial.
 13. The vehicle hull of claim 8, wherein the blast deflector is attached to the lower hull portion with at least one of mechanical attachment devices and adhesive material.
 14. The vehicle hull of claim 8, wherein the blast deflector is integral with the lower hull portion.
 15. A military vehicle comprising the vehicle hull of claim
 8. 16. A multiple layer vehicle hull, comprising: an upper hull portion having at least one butt weld; and a sacrificial lower hull portion below and semi-decoupled with the upper hull portion, the lower hull portion comprising a U-shaped base or a base having a bottom that is at least partially flat, and a sacrificial deflector beneath the lower hull portion.
 17. The vehicle hull of claim 16 further comprising a V-shaped blast deflector under the lower hull portion, the blast deflector having concave or convex walls.
 18. The vehicle hull of claim 16, wherein the upper hull portion has two butt welds, one creating a top seam running longitudinally relative to a length of a vehicle in a top central region, and one creating a bottom seam running longitudinally relative to the length of the vehicle in a bottom central region.
 19. The vehicle hull of claim 16, wherein the upper hull portion has three butt welds, creating three seams running substantially longitudinally relative to a length of a vehicle.
 20. (canceled) 